Machine safety guard

Abstract

A machine safety guard for stopping a machine during any phase of operation to prevent injury to workers in which a guard lever is disposed between the worker and the hazardous area of the machine and is connected on one end to a pivot shaft. An activating arm extends from the shaft and has a post for operating a microswitch which is connected to the emergency circuit of the machine. When the guard lever is touched the lever pivots on the shaft, thereby lowering the post from the microswitch, causing the emergency circuit to stop the machine. A counterweight is used to control the sensitivity of the guard lever.

We claim: 
     
       1. A safety guard for a production machine having an emergency circuit for stopping the machine, said safety guard comprising a guard lever disposed between the hazardous area of the machine where injury can occur and the machine operator and, in a first position, forming a shield restricting access to said hazardous area and, in a second position, permitting free access to said area, pivot means for connecting said guard lever at one end to the machine, an activating arm connected to said pivot means, a switch operated by movement of said arm and said lever, a generally horizontally positioned balance arm connected to said activating arm, a weight disposed and moveable longitudinally on said balance arm for controlling the force required to move said lever and to operate said switch, and an electric circuit connecting said switch to the emergency circuit of the production machine so that movement of said guard lever to said second position interrupts the machine operating cycle through the emergency circuit. 
     
     
       2. A safety guard as defined in claim 1 in which said pivot means includes a shaft disposed between said activating arm and said guard lever, generally perpendicular to said activating arm and said guard lever, and a bracket on said machine for rotatably holding said shaft. 
     
     
       3. A safety guard as defined in claim 2 in which one end of said shaft is connected to said guard lever and the other end of said shaft is connected to said activating arm. 
     
     
       4. A safety guard as defined in claim 2 in which said guard lever extends away from said shaft to one side of said bracket, and said activating arm extends away from said shaft to the other side of said bracket, in the opposite direction from said guard lever. 
     
     
       5. A safety guard as defined in claim 4 in which said balance arm extends from said activating arm perpendicular to said shaft, and said weight is disposed on said balance arm on the same side of said bracket as said guard lever. 
     
     
       6. A safety guard as defined in claim 4 in which one end of said shaft is connected to said guard lever, and the other end of said shaft is connected to said activator arm. 
     
     
       7. A safety guard as defined in claim 1 in which a shaft is connected to one end of said guard lever and is disposed generally perpendicular thereto, and said activating arm is connected to the end of said shaft opposite the end connected to said lever and extends generally perpendicular to said shaft in the opposite direction from said lever. 
     
     
       8. A safety guard as defined in claim 7 in which a balance arm extends from said activating arm past said shaft on the same side as said lever, and a counterweight is disposed on said balance arm on the same side of said shaft as said guard lever. 
     
     
       9. A safety guard as defined in claim 1 in which one end of said guard lever includes a substantially vertical end piece connected at the top thereof to said pivot means, and the opposite end of said guard lever includes an angular end piece for causing said guard lever to rise up when encountered by objects on that side. 
     
     
       10. A safety guard as defined in claim 1 in which a post is connected to said activating arm and operates said switch.